How do I implement specific phone number formatting with an EditText and ICS?

Question

My app requires that phone numbers be formatted like xxx-xxx-xxxx. The code below worked prior to ICS, but ICS devices completely ignore the formatting text watcher. Why does it ignore the formatter and how can I get ICS to follow the expected format?

I'm setting up the filter and text listener as:

final EditText phoneNumber = (EditText) findViewById(R.id.phoneNumber);
phoneNumber.addTextChangedListener(new PhoneNumberFormattingTextWatcher());
phoneNumber.setFilters(new InputFilter[] { new PhoneNumberFilter(), new InputFilter.LengthFilter(12) });

Code for the PhoneNumberFilter:

import android.text.InputType;
import android.text.Spanned;
import android.text.method.NumberKeyListener;

public class PhoneNumberFilter extends NumberKeyListener {

    @Override
    public int getInputType() {
        return InputType.TYPE_CLASS_PHONE;
    }

    @Override
    protected char[] getAcceptedChars() {
        return new char[] { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '-' };
    }

    @Override
    public CharSequence filter(CharSequence source, int start, int end,
            Spanned dest, int dstart, int dend) {

        // Don't let phone numbers start with 1
        if (dstart == 0 && source.equals("1")) 
            return "";

        return super.filter(source, start, end, dest, dstart, dend);
    }
}

Answer 1

I solved this with the following:

final EditText phoneNumber = (EditText) findViewById(R.id.phoneNumber);
phoneNumber.addTextChangedListener(new PhoneNumberTextWatcher());
phoneNumber.setFilters(new InputFilter[] { new PhoneNumberFilter(), new InputFilter.LengthFilter(12) });

PhoneNumberFilter - ensures that the phone number matches XXX-XXX-XXXX:

public class PhoneNumberFilter extends NumberKeyListener {

    @Override
    public int getInputType() {
        return InputType.TYPE_CLASS_PHONE;
    }

    @Override
    protected char[] getAcceptedChars() {
        return new char[] { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '-' };
    }

    @Override
    public CharSequence filter(CharSequence source, int start, int end,
            Spanned dest, int dstart, int dend) {

        // Don't let phone numbers start with 1
        if (dstart == 0 && source.equals("1")) 
            return "";

        if (end > start) {
            String destTxt = dest.toString();
            String resultingTxt = destTxt.substring(0, dstart) + source.subSequence(start, end) + destTxt.substring(dend);

            // Phone number must match xxx-xxx-xxxx
            if (!resultingTxt.matches ("^\\d{1,1}(\\d{1,1}(\\d{1,1}(\\-(\\d{1,1}(\\d{1,1}(\\d{1,1}(\\-(\\d{1,1}(\\d{1,1}(\\d{1,1}(\\d{1,1}?)?)?)?)?)?)?)?)?)?)?)?")) { 
                return "";
            }
        }
        return null;
    }
}

PhoneNumberTextWatcher - handles auto inserting dashes and auto removing dashes if the user is deleting:

public class PhoneNumberTextWatcher implements TextWatcher {

    private boolean isFormatting;
    private boolean deletingHyphen;
    private int hyphenStart;
    private boolean deletingBackward;

    @Override
    public void afterTextChanged(Editable text) {
        if (isFormatting)
            return;

        isFormatting = true;

        // If deleting hyphen, also delete character before or after it
        if (deletingHyphen && hyphenStart > 0) {
            if (deletingBackward) {
                if (hyphenStart - 1 < text.length()) {
                    text.delete(hyphenStart - 1, hyphenStart);
                }
            } else if (hyphenStart < text.length()) {
                text.delete(hyphenStart, hyphenStart + 1);
            }
        }
        if (text.length() == 3 || text.length() == 7) {
            text.append('-');
        }

        isFormatting = false;
    }

    @Override
    public void beforeTextChanged(CharSequence s, int start, int count, int after) {
        if (isFormatting)
            return;

        // Make sure user is deleting one char, without a selection
        final int selStart = Selection.getSelectionStart(s);
        final int selEnd = Selection.getSelectionEnd(s);
        if (s.length() > 1 // Can delete another character
                && count == 1 // Deleting only one character
                && after == 0 // Deleting
                && s.charAt(start) == '-' // a hyphen
                && selStart == selEnd) { // no selection
            deletingHyphen = true;
            hyphenStart = start;
            // Check if the user is deleting forward or backward
            if (selStart == start + 1) {
                deletingBackward = true;
            } else {
                deletingBackward = false;
            }
        } else {
            deletingHyphen = false;
        }
    }

    @Override
    public void onTextChanged(CharSequence s, int start, int before, int count) {
    }
}